14 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



grayish white; under parts without black, except sometimes a 



jugular area Herpsilochmus (extralimital).a 



hh. Rectrices 10 Drymophila (extralimital) . b 



ee. Planta tarsi entire (fused). 

 /. Bill decidedly longer than head, more than one-third as long as wing. 

 g. Tail four-fifths as long as wing, graduated; exposed culmen longer 

 than tarsus, the latter much less than half as long as wing. 



Ramphocaenus (p. 84). 



gg. Tail but little more than half as long as wing, rounded; exposed 



culmen much shorter than tarsus, the latter nearly half as long as 



wing Microbates (p. 88). 



ff. Bill not longer than head (usually shorter), less than one-third as long 

 as wing. 

 g. Rictal bristles well developed. 



h. Rectrices 10; bill much narrower and relatively deeper at base; 



tarsus longer than commissure Cercomacra (p. 90). 



hh. Rectrices 12; bill much broader and more depressed at base; 

 tarsus shorter than commissure.. Thamnomanes (extralimital). c 

 gg. Rictal bristles indistinct (usually obsolete). 



h. Loral and frontal regions very densely feathered, the feathering 



erect, plush-Uke Pyriglena (extralimital). <* 



hh. Loral and frontal regions normally feathered, scantily feathered, 

 or sometimes naked. 

 i. Frontal and loral regions normally (densely) feathered. 

 j. Rictal region naked, postocular region wholly* feathered; larger 

 forms (total length about 125 mm.), with mostly plain colora- 

 tion Myrmoborus (extralimital). « 



o Herpsilochmus Cabanis, in Wiegmann's Archiv fur Naturg., xiii, pt. i, 1847, 224. 

 Type, Myiothcra pileata Lichtenstein. — Dendrooecia Bertoni, Aves Nuevas del Para- 

 guay, 1901, 138. Type, D. erythroptera Bertom= Myiothera rufimarginata Temminck. 

 (Nearly the whole of tropical South America east of the Andes; about eleven species 

 recognized, of which, however, the present writer has examined only four.) I am 

 not able to find any structural characters separating Herpsilochmus from Microrhopias. 



b Formicivora (not Formicivorus Temminck, 1807) Swainson, Zool. Journ., ii, 1825, 

 145. Type, Myiothera squamata Lichtenstein. — Drymophila Such (ex Swainson), Zool. 

 Journ., i, Jan., 1825, 559. Type, D. variegata Such= Myiothera ferruginea Lich- 

 tenstein.— Ellipur a Cabanis, in Wiegmann's Archiv fiir Naturg., xiii, pt. i, 1847, 

 228. Type, Myiothera ferruginea Lichtenstein. — Stipituropsis Bertoni, Aves Nuevas 

 del Paraguay, 1901, 141. Type, S. arechavaletse 'Bevtoni= Formicivora genei De 

 Filippi. 



c Thamnomanes Cabanis, in Wiegmann's Archiv fiir Naturg., xiii, pt. i, 1847, 230. 

 Type, Lanius cnesius Lichtenstein. (Colombia and Guiana to southeastern Brazil 

 and upper Amazon Valley; two species.) 



d Pyriglena Cabanis, in Wiegmann's Archiv fiir Naturg., xiii, pt. i, 1847, 211. 

 Type, Lanius domicella Lichtenstein = TttrrfMs leucopterus Vieillot. (Ecuador and 

 Peru to southeastern Brazil; five species recognized, of which the present writer 

 has examined only P. leucoptera (Vieillot) and P. atra (Swainson).) 



e Myrmoborus Cabanis and Heine, Mus. Hein., ii, July, 1859, 9. Type, Pithys 

 leucophrys Tschudi. Besides the type species, I would refer the following to this 

 genus: M. myiotherinus (Spix) and M. luguhris Cabanis; probably also Hypocnemis 

 schistacea Sclater and H. melanura Sclater and Salvin, and possibly H. melanopogon 

 Sclater, but these three species I have not seen. 



